Insecticide



INSECTIMDE David R. Merrill, Long Beach, Caliii, assignor to Union Oil Company of California, Los Angeles, Calif., a corporation of California No Drawing. Application May 2, 1939,

' Serial No. 271,283

7 Claim.

This invention relates to insecticides, particularly to insecticidal sprays such as fly sprays, cattle sprays and the like wherein the active agent is contained in a carrier or solvent, and it also relates to insecticides in which the active agent is carried on an inert or active dry carrier or dust, or also in unctious form.

The object or the present invention is to provide insecticides oi the type indicated containing as an important active constituent a material of greater repellent value than heretofore employed in commercial uses of the indicated type, and wherein the repellent material employed in the various carriers is non-volatile, non-subliming and stable.

according to this invention, the active constituent is an alkyl ester of a terpene dicarboxylic acid, and specifically the invention involves an alkyl ester (e. e. diethyl ester) of a polybasic acid of terpene origin produced from an anhydride known as 3-isopropyl-d-rnethyl-3,6-endoethylene- A tetrahydro phthalic anhydride. Since the anhydride actually employed as the startingmaterial is a commercial synthetic product containing; polymeric materials, the ester product also contains lymeric materials in minor quantities. This material also has the characteristic 01-increasing toxic action of other materials which have in themselves toxic action, such as pyrethrin, derris extracts and kindred organic toxic materials usable in sprays of this type.

The invention resides in the use of such alkyl ester from said substituted polybasic acid anhydride as an insecticide. The invention also resides in a mineral oil fraction as a carrier for said alkyl ester. Such a fraction may be kerosene or the like where the material is to be used for fly sprays for example, or it may be a less volatile heavier material commonly known as mineral spray oil, or other appropriate fraction. The invention also resides in the use of said modified terpene esters in any other appropriate carrier such as a dust or unctious body. Also the invention resides in compositions containing the mentioned esters which also additionally contain toxic agents such as pyrethrurn and the like whose toxic action is increased through'the presence of said esters.

The allnrl tetrahydro phthalic anhydride employed for production of the esters of this invention may be obtained on the market under the trade name Petrex manufactured by Hercules Powder Company, this material also containing a small quantity of polymeric materials. The essential constituent is the phthalic anhydride substitution product mentioned which is a synthetic, resinous, polybasic acid anhydride of terpene origin. This anhydride is substantially non-volatile, does not sublime on heating andretains its pale yellow color at elevated temperatures. It possesses an acid number of about 530, has a softening point of ill i to lit, a specific grayity of l.l5, and is soluble in alcohols, various drying oils, acetates, coal tar hydrocarbons, mineral spirits and other petroleum fractions such as kerosene, mineral spray oils and similar light mineral oil fractions adapted to insecticidal uses.

Said substituted phthalic anhydride appears to be 3-isopropyl-6-rnethyl 3,6 endoethylene-M- tetrahydro phthalic anl iydride, having the following indicated structure, and an ester of the invention has the corresponding indicated structure where R is an alkyl group:

Anhydride Di-cster CH: CH3 t t H O H O H e tear Haj is new I l I 0 i i I H-l CH2 OC HC CH2 C-C-O-R /ii ii HaC-JJ-CH3 H3C( 3CH3 1'; 1'1

The above materials are of terpene origin as is apparent from a well known terpene (C10H1c) having the structure:

CIIHs c HzC equal parts of alcohol and water'containing 6%.

sodium hydroxide. The separated solution contains the mono-ester which may be in turn separated by acidifying the extract and washing. The di-ester, which did not enter into the extracting solution, was recovered simply by washing with water in the cold. The di-ester product is a yellowish to orange liquid of high viscosity approximating that of heavy lubricating oil. It has an acid number of 0.72 and a saponification number of 306. The mono-ester is normally con-' siderably more viscous than the di-ester and is nearly solid. The boiling point of both esters is above 400 F. The acid number of the monoester is considerably higher than that of the diester being about 154. Both are soluble in alcohols, mineral spirits, mineral oil fractions and the like and, being highly stable, are well adapted to the present uses, especially in view of the fact that they have high repellent values for insecticidal purposes. By somewhat similar procedures, obvious to the skilled chemist, other alkyl esters of the lower alcohols also may be produced and employed, such as the lower alkyl esters methyl, propyl and butyl esters.

The above described alkyl ester products of the indicated terpene dicarboxylic acid which are herein sometimes referred to as Petrex" esters for convenience, are added to various petroleum oils suitable for individual purposes, in concentrations varying from about 1% to about 10%. Perhaps a good general average is in the vicinity of 3% to 5% based on the oil fraction employed. For the purpose of fly sprays an appropriate cut in the kerosene range, which may be if desired either in the nature of a light kerosene cut or a heavy kerosene cut, may be employed. For other uses it may be desirable to employ heavier maf terials such as spray oils, for example where making up cattle sprays. Mineral spray oils are well known in the agricultural industry. They are lighter than ordinary light lubricating oils, although they have lubricating characteristics, and

possess viscosities in the order of about 50 to 125 seconds Saybolt Universal at 100 F. Such. oils for horticultural uses commonly possess highly unsulfonatable residues in the neighborhood of Ong. However, oils in these viscosity ranges may possess lower unsulfonatable residues, for example in the range of to deOng or even lower or higher as uses may permit.

As a specific example, 5% of ethyl Petrex, as above described, employed in a kerosene type out in the range commonly used for fly sprays has been employed and found to be highly preferable as a repellent to all other types of synthetic material used in the same concentration. I

In addition to using the Petrex ester in petroleum fractions as described, it may be desirable to add other insecticidal constituents-such as pyrethrum, or derris or cube extracts, or alkyl thiocyanates, and the like. In some instances it may be preferable to prepare the insecticide as a dust in which case it may be carried in an inert carrier such as diatomaceous earth or it may be carried on an active carrier such as powdered pyrethrum flowers or ground derris root or the like. Again the Petrex alkyl esters may be carried in an unctious type carrier such as lanolin or other greasy or pasty material.

It is to be understood that; these disclosures are given as illustrative of the generic invention within the scope of the appended claims, rather than as limiting thereof.

I claim:

1. An insecticide comprising a lower alkyl ester of 3-isopropyl 6-methyl 3,6-endoethylene A -tetrahydro-phthalic acid.

2. An insecticide according to claim 1 wherein the ester is one of the class consisting of methyl, ethyl, propyl and butyl esters.

3. An insecticide according to claim 1 wherein the ester is the di-ethyl ester.

4. An insecticide according to claim 1 including a mineral oil fraction as a carrier.

5. An insecticide according to claim 1- including a carrier and wherein the ester is one of the class consisting of methyl, ethyl, propyl and butyl esters.

6. An insecticide comprising a slowly volatilizing petroleum fraction, and a low alkyl ester of 3-isopropyl B-methyl 3,6-endoethylene A -tetrahydro-phthalic acid.

7. An insecticide according to claim 6 wherein the ester is the ester of an alcohol of the group consisting of methyl, ethyl, propyl and butyl alcohols.

DAVID R. MERRILL. 

